1. Field of the Invention
This invention relates to a disk reproducing apparatus and, more specifically, to a minidisk loading mechanism for a multiple disk reproducing apparatus capable of storing a plurality of minidisks, i.e., the so-called MDs, for continuous reproducing operation.
2. Description of the Prior Art
A disk reproducing apparatus, similarly to a disk recording apparatus, is provided with a multidisk loading mechanism capable of storing a plurality of disks, automatically taking out the disks in a predetermined order, loading the disk into a reproducing unit, and returning the disk from the reproducing unit to its storage position after the information recorded on the disk has been reproduced.
Since a multidisk loading mechanism designed specially for a minidisk reproducing apparatus has not generally been known, a CD apparatus, which is similar to a minidisk reproducing apparatus, will be described.
FIG. 38 shows a disk loading mechanism analogous with a known multidisk loading mechanism disclosed in Japanese Utility Model Laid-open (Kokai) No. 4-20674. Shown in FIG. 38 are a frame 1, a pivotal shaft 2, a CD reproducing apparatus 3, a plurality of CD holders 4, a pivotal pin 5, a recess 6 formed in each CD holder 4.
The operation of the multidisk loading mechanism shown in FIG. 38 will be described with reference to FIGS. 39 and 40. Each CD holder 4 having the shape of a case holds a CD (compact disk) 7 therein. The plurality of CD holders 4 are supported for turning relative to the frame 1 on the pivotal pin 5. The frame 1 is able to turn on the pivotal shaft 2. The frame 1 is turned on the pivotal shaft 2 in the direction of the arrow (FIG. 39) to take out the frame 1 holding the CD holders 4 from the CD reproducing apparatus 3. In this state, the CDs 7 can be taken out from and put into the CD holders 4.
When playing the CDs 7, the frame 1 is turned to a loading position 26 (FIG. 40) outside the CD reproducing apparatus 3 as shown in FIG. 39, the CDs 7 are inserted in the CD holders 4, respectively, and then the frame 1 is turned to a standby position 27 (FIG. 40) inside the CD reproducing apparatus 3 as shown in FIG. 38. Then, a piece of music is specified by operating a selector key, not shown, to make a control circuit, not shown, select the specified piece of music. Then, the CD holder 4 holding the CD 7 storing the specified piece of music is turned on the pivotal pin 5 to a reproducing position 28 (FIG. 40). During the operation of the CD reproducing apparatus 3, all the CDs 7 are held at the standby position 27 inside the CD reproducing apparatus 3 and covered with the frame 1 to protect the CDs 7 from dust. In this state, however, the CDs 7 are hidden from view.
Referring to FIG. 40, a signal converting head (hereinafter referred to as “sensor”) for reading information from and writing information on the CDs 7 moves along an alternate long and short dash line. When the CD reproducing apparatus 3 is installed with a plane in which the CD holder 4 is moved in a vertical position, the sensor moves vertically. When the CD reproducing apparatus 3 is installed with the plane in which the CD holder 4 is moved in a horizontal position, the sensor moves horizontally. However, since the sensor is comparatively heavy, facility in moving the sensor affecting reproducing performance is greatly dependent on the position in which the CD reproducing apparatus 3 is installed. A minidisk reproducing apparatus is similar in construction as the CD reproducing apparatus 3, except that the minidisk reproducing apparatus is constructed so as to use minidisks contained in cartridges.
The construction of a minidisk cartridge will be described to facilitate understanding the present invention. FIG. 41 is a perspective view of the front side of a minidisk cartridge disclosed in Japanese Patent Laid-open (Kokai) No. 4-278269, and FIG. 42 is a perspective view of the back side of the same minidisk cartridge. Referring to FIGS. 41 and 42, a minidisk cartridge (hereinafter referred to simply as “cartridge”) 25 has a flat case 13 containing a disk 16, a shutter 14 put on the case 13 for sliding movement in the direction of the arrow (FIG. 41) to open an opening through which access to the disk 16 can be gained, and a key 15 provided on the case 13 to lock the shutter 14 at the closed position. When one end of the key 15 disposed within a groove 17 formed in a side wall of the case 13 is depressed, the key 15 releases the shutter 14 to enable the shutter 14 to be moved in the direction of the arrow.
An opening 18 is formed in the central area of the back wall of the case 13 and a center plate 19 fastened to the disk 16 is exposed in the opening 18. A plurality of holes 20 and recesses 22 for positioning the case 13 and transferring the cartridge 25 are formed in the back wall of the case 13. A mark 21 indicating the direction of insertion of the cartridge 25 is formed near one side of the case 13 on the back surface of the case 13. Corners at the opposite ends of the side near the mark 21 are rounded. The cartridge 25 is inserted in a reproducing apparatus, not shown, in the direction indicated by the mark 21.
Referring to FIG. 43 showing the back end surface 24 of the case 13 of the cartridge 25, a label having the description of the contents, such as titles of pieces of music, name of data, title or the like, of the disk 16 contained in the case 13 is attached to the outer surface of the back end surface 24 of the case 13. Since other side walls are used for functional purposes, the label 13 is not allowed to be attached to the side walls other than the back end surface 24.
Referring to FIGS. 44, 45 and 46 showing a disk loading unit included in a CD reproducing apparatus disclosed in Japanese Utility Model 62-63853, there are shown a disk 7, a magnetic turntable 62 on which the disk 7 is supported and held in place magnetically, a floating deck 60 supporting the turntable 62 for rotation, a base plate 59, damping supports 64 supporting the floating deck 60 in a floating state on the base plate 59, locking pins 65 projecting from the opposite sides of the front and back ends of the floating deck 60, and locking plates 67 that engage the locking pins 65 to fix the floating deck 60 relative to the base plate 59 when mounting the disk 7 on the magnetic turntable 62. A disk mounting mechanism, not shown, for mounting the disk 7 on the magnetic turntable 62 is disposed over the floating deck 60 lowers the disk 7 from a position at a height A toward the magnetic turntable 62 so that the disk mounting mechanism and the magnetic turntable 62 supported on the base plate 59 will not interfere with each other when the disk mounting mechanism locates the disk 7 above the magnetic turntable 62.
Since the position of an optical pickup head, not shown, must precisely be controlled when reading information from the disk 7 with the optical pickup head, the floating deck 60 holding the optical pickup head and a disk driving motor, not shown, is supported in a floating state on the base plate 59 by the damping supports 64 to avoid the adverse influence of disturbing external vibrations on the reading operation of the optical pickup head. Therefore, when mounting the disk 7 on the magnetic turntable 62, the locking plates 67 are brought into engagement with the locking pins 65 to lock the floating deck 60 holding the magnetic turntable 62 in place because the disk 7 cannot correctly be mounted on the magnetic turntable 62 if the turntable is unstable, and then the disk 7 is lowered toward and mounted on the magnetic turntable 62. The disk mounting mechanism lowers the disk 7 from a position at the height A higher than a height B at which the disk 7 is seated on the magnetic turntable 62 by a height difference C necessary for preventing the interference between the disk 7 and the magnetic turntable 62.
The disk loading mechanism thus constructed of the conventional multidisk reproducing apparatus has the following problems.                1) It is impossible to find visually which CD holders are empty and which CD holders are loaded with CDs while the multidisk reproducing apparatus is in operation.        2) The contents of the CDs stored in the CD holders at the standby position cannot be read.        3) The CDs stored in the CD holders cannot be taken out or changed while the multidisk reproducing apparatus is in operation.        4) The frame 1 must have a strong construction because the frame 1 moves all the CDs together and hence the disk loading mechanism is comparatively heavy.        5) Since the CD holders are supported by the pivotal pin 5 on the frame 1 in a cantilever fashion, the pivotal pin 5 must be comparatively long to support the CD holders so that the CD holders will not decline and, consequently, the thickness of the stack of the CD holders is large as compared with the thickness of the plurality of CDs.        6) Since the sensor for reading information from the CD of the multidisk reproducing apparatus moves straight relative to the front side of the multidisk reproducing apparatus, the direction of the gravitational acceleration acting on the sensor changes when the position of the multidisk reproducing apparatus is changed and hence the multidisk reproducing apparatus must be installed in a specified position.        7) Since the locking plates 67 engage the locking pins 65 with the floating deck 60 supported at its original position by the damping supports 64, the disk must be inserted into the disk loading mechanism at a position above the magnetic turntable 62 and lowered toward the magnetic turntable 62, which inevitably increases the size of the CD reproducing apparatus.        8) Since the floating deck moves vertically within the range of stroke of the damping supports 64, additional spaces must be secured above and under the cartridge, which increases the size of the CD reproducing apparatus.        9) Since the thickness of the CD reproducing apparatus is dependent % on the range of vertical movement of the elevator, the size of the CD reproducing apparatus is increased if the thickness of the elevator driving unit is added to the range of vertical movement of the elevator.        10) Although the stopping position of the elevator must accurately correspond to the height of the cartridge, the stopping position often deviates from the correct position due to the inertia of the driving mechanism or external vibrations.        